THREAD
SIZE

DRILL
DIAMETER

TAP DRILL
SIZE

Coarse Thread

1-64

.0595

No. 53

2-56

.0700

No. 50

3-48

.0785

No. 47

4-40

.0890

No. 43

5-40

.1015

No. 38

6-32

.1065

No. 36

8-32

.1360

No. 29

10-24

.1495

No. 25

12-24

.1770

No. 16

1/4-20

.2010

No. 7

5/16-18

.2570

'F'

3/8-16

.3125

5/16

7/16-14

.3680

'U'

1/2-13

.4219

27/64

9/16-12

.4844

31/64

5/8-11

.5312

17/32

3/4-10

.6562

21/32

7/8-9

.7656

49/64

1"-8

.8750

7/8

Fine Thread

0-80

.0469

3/64

1-72

.0595

No. 53

2-64

.0700

No. 50

3-56

.0820

No. 45

4-48

.0935

No. 42

5-44

.1040

No. 37

6-40

.1130

No. 33

8-36

.1360

No. 29

10-32

.1590

No. 21

12-28

.1820

No. 14

1/4-28

.2130

No. 3

5/16-24

.2720

'I'

3/8-24

.3320

'Q'

7/16-20

.3906

25/64

1/2-20

.4531

29/64

9/16-18

.5156

33/64

5/8-18

.5781

37/64

3/4-16

.6875

11/16

7/8-14

.8125

13/16

1"-14

.9375

59/64